Organic compound and light emitting diode and organic light emitting diode display device using the same

ABSTRACT

The present disclosure relates to an organic compound, a light emitting diode and an organic light emitting diode display device using the same. The organic compound is represented by a following chemical formula 1.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit under 35 U.S.C. § 119(a) ofKorean Patent Application No. 10-2016-0168918, filed on Dec. 12, 2016,in the Korean Intellectual Property Office, which is incorporated hereinby reference in its entirety into the present application.

BACKGROUND 1. Technical Field

The present disclosure relates to an organic compound, and moreparticularly, to an organic compound where a driving voltage and anemission efficiency are improved and a light emitting diode and anorganic light emitting diode display device including the organiccompound.

2. Discussion of the Related Art

Requests for a flat panel display having a small space have increaseddue to demand for display devices. Among various flat panel displays, anorganic light emitting diode (OLED) display device, which may bereferred to as an organic electroluminescent display (OELD) device,including a light emitting diode (LED) has been the subject of recentresearch.

The LED is an element where a hole and an electron are injected into anemitting material layer from an anode (a hole injecting electrode) and acathode (an electron injecting electrode) to constitute an exciton andthe emitting material layer emits a light due to transition of theexciton. The LED has an advantage such that an element is formed on aflexible transparent substrate such as plastic. In addition, the LED hasa relatively low driving voltage (equal to or lower than 10V), arelatively low power consumption and an excellent color property.

Recently, the LED emitting a white colored light has been applied tovarious fields such as a thin light source, a light source of abacklight unit for a liquid crystal display (LCD) device and a lightsource for a full color display device having a color filter layer aswell as lighting.

In the white LED, a color purity, a color stability according tovariation of current and voltage and a capability of fabrication as wellas a high efficiency and a long lifetime have been the subject. Thewhite LED may be classified into a single stack structure and a multiplestack structure. To obtain the white LED having a relatively longlifetime, the LED having a tandem structure where a plurality ofemitting units are laminated has been widely used.

For example, the white LED may have the tandem structure where a firstemitting part including a blue emitting layer and a second emitting partincluding a yellow-green emitting layer are vertically laminated. Thewhite LED may emit the white colored light by mixing a light emittedfrom the blue emitting layer and a light emitted from the yellow-greenemitting layer.

In the LED having the tandem structure, a charge generation layer isformed between the first and second emitting parts to increase a currentefficiency of each emitting layer and to smoothly distribute charges toeach emitting layer. In general, the charge generation layer may have apositive negative (PN) junction structure where an N type chargegeneration layer and a P type charge generation layer are sequentiallyformed.

In the charge generation layer of the tandem structure, a charge isgenerated at an interface between the P type charge generation layer anda hole injecting layer or a hole transporting layer due to an energylevel difference between the N type charge generation layer and the Ptype charge generation layer. As a result, an electron injectionproperty into the N type charge generation layer is deteriorated.

Further, when the N type charge generation layer is doped with a metal,the metal diffuses to the P type charge generation layer and a lifetimeof the LED is reduced. Specifically, a material for the chargegeneration layer has a disadvantage in a thermal stability and anelectric stability. When the white LED operates for a relatively longtime, the material for the charge generation layer is deteriorated orspoiled. Accordingly, an injection efficiency of an electron generatedat the interface between the P type charge generation layer and a holeinjecting layer or a hole transporting layer the into the N type chargegeneration layer is reduced. Since the electron is not injected from theN type charge generation layer into the adjacent electron transportinglayer, a property of the LED is deteriorated and a lifetime of the LEDis reduced.

SUMMARY

Embodiments relate to an organic compound where an aryl group isconnected to a phenanthroline moiety having at least one substitutedaromatic ring through at least one linker.

For example, an organic compound of the present disclosure may berepresented by a following chemical formula 1.

In the chemical formula 1, each of R₁ to R₆ is independently one ofhydrogen, deuterium, tritium, a non-substituted or substituted alkylgroup of C1 to C20, a non-substituted or substituted alkoxy group of C1to C20, a non-substituted or substituted aryl group of C5 to C60 and anon-substituted or substituted hetero aryl group of C4 to C60; each ofL₁ and L₂ is independently one of a non-substituted or substitutedarylene group of C5 to C60 and a non-substituted or substituted heteroarylene group of C5 to C60;a is 0 or 1; and each of Ar₁ and Ar₂ isindependently one of a non-substituted or substituted aryl group of C5to C60 and a non-substituted or substituted hetero aryl group of C4 toC30.

One or more embodiments relate to a light emitting diode having a tandemstructure where the organic compound is applied to a charge generationlayer and/or an electron transporting layer and an organic lightemitting diode display device.

Advantages and features of the disclosure will be set forth in part inthe description, which follows and in part will become apparent to thosehaving ordinary skill in the art upon examination of the following ormay be learned from practice of the disclosure. Other advantages andfeatures of the embodiments herein may be realized and attained by thestructure particularly pointed out in the written description and claimshereof as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description are explanatory, and are intended toprovide further explanation of the embodiments as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure, are incorporated in and constitute apart of this specification, illustrate implementations of the disclosureand together with the description serve to explain the principles ofembodiments of the disclosure.

FIG. 1 is a cross-sectional view showing a light emitting diode of atandem structure having two emitting parts according to a firstembodiment of the present disclosure.

FIG. 2 is a cross-sectional view showing a light emitting diode of atandem structure having three emitting parts according to a secondembodiment of the present disclosure.

FIG. 3 is a cross-sectional view showing an organic light emitting diodedisplay device according to a third embodiment of the presentdisclosure.

FIG. 4A is a graph showing a voltage-current density property of lightemitting diodes of the embodiment 1 and the comparative example 1.

FIG. 4B is a graph showing a brightness-current efficiency property oflight emitting diodes of the embodiment 1 and the comparative example 1.

FIG. 4C. is a graph showing a brightness-external quantum efficiency(EQE) property of light emitting diodes of the embodiment 1 and thecomparative example 1.

FIG. 4D is a graph showing a lifetime property of light emitting diodesof the embodiment 1 and the comparative example 1.

FIG. 5A is a graph showing a voltage-current density property of lightemitting diodes of the embodiment 2 and the comparative example 2.

FIG. 5B is a graph showing a brightness-current efficiency property oflight emitting diodes of the embodiment 2 and the comparative example 2.

FIG. 5C is a graph showing a brightness-external quantum efficiency(EQE) property of light emitting diodes of the embodiment 2 and thecomparative example 2.

FIG. 5D is a graph showing a lifetime property of light emitting diodesof the embodiment 2 and the comparative example 2.

FIG. 6A is a graph showing a voltage-current density property of lightemitting diodes of the embodiment 3 and the comparative example 3.

FIG. 6B is a graph showing a brightness-current efficiency property oflight emitting diodes of the embodiment 3 and the comparative example 3.

FIG. 6C is a graph showing a brightness-external quantum efficiency(EQE) property of light emitting diodes of the embodiment 3 and thecomparative example 3.

FIG. 6D is a graph showing a lifetime property of light emitting diodesof the embodiment 3 and the comparative example 3.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings. In the following description, when a detailed description ofwell-known functions or configurations related to this document isdetermined to unnecessarily cloud a gist of an embodiment of thedisclosure, the detailed description thereof will be omitted. Theprogression of processing steps and/or operations described is anexample; however, the sequence of steps and/or operations is not limitedto that set forth herein and may be changed as is known in the art, withthe exception of steps and/or operations necessarily occurring in acertain order. Like reference numerals designate like elementsthroughout. Names of the respective elements used in the followingexplanations are selected only for convenience of writing thespecification and may be thus different from those used in actualproducts.

[Organic Compound]

Embodiments relate to an organic compound where an aryl group isconnected to a phenanthroline moiety having at least one substitutedaromatic ring through at least one linker. For example, an organiccompound of the present disclosure may be represented by a followingchemical formula 1.

In the chemical formula 1, each of R₁ to R₆ is independently one ofhydrogen, deuterium, tritium, a non-substituted or substituted alkylgroup of C1 to C20, a non-substituted or substituted alkoxy group of C1to C20, a non-substituted or substituted aryl group of C5 to C60 and anon-substituted or substituted hetero aryl group of C4 to C60; each ofL₁ and L₂ is independently one of a non-substituted or substitutedarylene group of C5 to C60 and a non-substituted or substituted heteroarylene group of C5 to C60; a is 0 or 1; and each of Ar₁ and Ar₂ isindependently one of a non-substituted or substituted aryl group of C5to C60 and a non-substituted or substituted hetero aryl group of C4 toC30.

The term ‘non-substituted’ preferably means that a hydrogen atom isbonded, and the hydrogen atom includes protium, deuteriumand tritium inthis case.

A substituent for the word ‘substituted’ includes one of anon-substituted or substituted with halogen alkyl group of C1 to C20, anon-substituted or substituted with halogen alkoxy group of C1 to C20,halogen, a cyano group, a carboxyl group, a carbonyl group, an aminegroup, an alkylamine group of C1 to C20, a nitro group, a hydrazylgroup, a sulfonyl group, an alkyl silyl group of C1 to C20, an alkoxysilyl group of C1 to C20, a cycloalkyl silyl group of C3 to C30, an arylsilyl group of C5 to C30, a non-substituted or substituted aryl group ofC5 to C30 and a hetero aryl group of C4 to C30.

The word ‘hetero’ in ‘a hetero aromatic ring,’ ‘a hetero cycloalkylenegroup,’ ‘a hetero arylene group,’ ‘a hetero arylalkylene group,’ ‘ahetero oxyarylene group,’ ‘a hetero cycloalkyl group,’ ‘a hetero arylgroup,’ ‘a hetero arylalkyl group,’ ‘a hetero oxyaryl group’ and ‘ahetero aryl amine group’ means that at least one (e.g., one to five)carbon atoms constituting an aromatic ring or an alicyclic ring issubstituted with at least one hetero atom selected from the groupincluding N, O, P, Si, S and a combination thereof.

In the chemical formula 1, the organic compound of the presentdisclosure includes a phenanthroline moiety. Due to the phenanthrolinemoiety, transporting property of an electron is improved and diffusionof an alkali metal or an alkali earth metal from an N type chargegeneration layer to a P type charge generation layer is prevented.Further, the phenanthroline moiety is substituted with an aromatic ring,such as at least one aryl group or a hetero aryl group Ar1. Accordingly,a thermal stability as well as transporting property of an electron isimproved in the organic compound according to the present disclosure.

In an exemplary embodiment, each of R₁ to R₆ may be independently one ofhydrogen, deuterium, tritium, a non-substituted or substituted alkylgroup of C1 to C20, a non-substituted or substituted alkoxy group of C1to C20.

In the chemical formula 1, each of Ar₁ and Ar₂ may be independently oneof a non-substituted or substituted aryl group and a non-substituted orsubstituted hetero aryl group. In an exemplary embodiment, each of Ar₁and Ar₂ may include a non-substituted or substituted aromatic ring. Forexample, each of Ar₁ and Ar₂ may be independently one of anon-substituted or substituted phenyl, biphenyl, terphenyl, naphthalene,anthracene, indene, indenoindene, heptalenyl, biphenylenyl, indacenyl,phenalenyl, phenanthrenyl, benzophenanthrenyl, dibenzophenanthrenyl,azulenyl, pyrenyl, fluoranthenyl, triphenylenyl, chrysenyl,tetraphenyl,fluoroanthenyl, tetracenyl, pleiadenyl, picenyl,pentaphenyl, pentacenyl, fluorenyl, indenofluorenyl, diazafluorenyl, ora non-fused or fused homo aryl such as spirofluorenyl and/or pyrolyl,pyridinyl, terpyridinyl, phenylpyridinyl, pyrimidinyl,pyridazinyl,triazinyl, tetrazinyl, imidazolyl, pyrazolyl, indolyl, isoindolyl,indazolyl, indolizinyl, pyrolizinyl, carbazolyl, benzocarbazolyl,dibenzocarbazolyl,indolocarbazolyl, indenocarbazolyl,benzofurocarbazolyl, benzothiocarbazolyl, quinolinyl, isoquinolinyl,phthalazinyl, quinoxalinyl, cynolinyl, quinazolinyl, quinozolinyl,quinolizinyl, furyl, benzoquinolinyl, benzoisoquinolinyl,benzoquinazolinyl, benzoquinoxalinyl, acridinyl, phenanthrolinyl,phenanthrenyl, pyrimidinyl, phenanthridinyl, pteridinyl,naphthylridinyl, naphtharidinyl, furanyl, pyranyl, oxazinyl, oxazolyl,oxadiazolyl, triazolyl, dioxinyl, benzofuranyl, dibenzofuranyl,arylthiazolyl, thiopyranyl, xanthenyl, chromenyl, isochromenyl,thioazinyl, thiophenyl,benzothiophenyl, dibenzothiophenyl, carbolinyl,difuropyrazinyl, benzofurodibenzofuranyl, benzothiodibenzofuranyl, or anon-fused or fused hetero aryl such as N-substituted spiro fluorenyl.

For example, each of Ar1 and Ar2 may be independently selected from agroup including phenyl, alkylphenyl, biphenyl, alkylbiphenyl,halophenyl, alkoxyphenyl, haloalkoxyphenyl, cyanophenyl,silylphenyl,naphthyl, alkylnaphthyl, halonaphthyl, cyanonaphthyl,silylnaphthyl, phenylnaphthyl,pyridyl, alkylpyridyl, halopyridyl,cyanopyridyl, alkoxypyridyl, silylpyridyl, phenylpyridyl, pyrimidyl,halopyrimidyl, cyanopyridimyl, alkoxypyrimidyl, phenylpyrimidyl,quinolinyl, isoquinolinyl, phenylquinolinyl, quinoxalinyl, pyrazinyl,quinazolinyl, naphthyridinyl, benzothiophenyl, benzofuranyl,dibenzothiophenyl, arylthiazolyl, dibenzofuranyl, fluorenyl, carbazoyl,imidazolyl, carbolinyl, phenanthrenyl, terphenyl, terpyridinyl,phenylterpyridinyl, triphenylenyl, fluoranthenyl and diazafluorenyl.

In an exemplary embodiment, Ar₁ is a homo aryl group such as asubstituted or non-substituted phenyl, biphenyl and naphthyl, and Ar₂ isa homo aryl group, such as a substituted or non-substituted phenyl,naphthyl, anthracenyl, phenalenyl, phenanthrenyl, pyrenyl,triphenylenyl, chrysenyl, fluoranthenyl, fluorenyl, diphenylfluorenyland spirofluorenyl, or a hetero aryl group, such as a substituted ornon-substitutedpyridyl, pyrazinyl, pyrimidyl, pyridazinyl, triazinyl,quinolinyl, isoquinolinyl, phthalazinyl, quinoxalinyl, cynolinyl,quinazolinyl, quinozolinyl, quinolizinyl and carbazolyl. Although Ar₂ ofa hetero aryl group may include one or two of an aromatic ring in anexemplary embodiment, the present disclosure is not limited to that setforth herein.

In the chemical formula 1, each of L1 and L2 may be independentlyselected from a group including a non-substituted or substitutedphenylene, biphenylene, terphenylene, tetraphenylene,indenylene,naphthylene, azulenylene, indacenylene, acenaphthylene, fluorenylene,spirofluorenylene, phenalenylene,phenanthrenylene, anthracenylene,fluoranthrenylene, triphenylenylene, pyrenylene, chrysenylene,naphthacenylene, picenylene, perylenylene, pentaphenylene, hexacenylene,pyrrolylene, imidazolylene, pyrazolylene, pyridinylene, pyrazinylene,pyrimidinylene, pyridazinylene, isoindolylene, indolylene, indazolylene,purinylene, quinolinylene, isoquinolinylene, benzoquinolinylene,phthalazinylene, naphthyridinylene, quinoxalinylene, quinazolinylene,benzoi soquinolinylene, benzoquinazolinylene, benzoquinoxalinylene,cinnolinylene, phenanthridinylene, acridinylene,phenanthrolinylene,phenazinylene, benzoxazolylene,benzimidazolylene,furanylene, benzofuranylene, thiophenylene,benzothiophenylene, thiazolylene, isothiazolylene, benzothiazolylene,isoxazolylene, oxazolylene, triazolylene, tetrazolylene, oxadiazolylene,arylthiazolylene, triazinylene, dibenzofuranylene, dibenzothiophenylene,carbazolylene, benzocarbazolylene,dibenzocarbazolylene,indolocarbazolylene, indenocarbazolylene,imidazopyrimidinylene and imidazopyridinylene.

For example, each of L1 and L2 may be independently selected from agroup including phenylene, alkylphenylene, cyanophenylene, naphthylene,alkylnaphthylene, biphenylene, alkylbiphenylene, anthracenylene,triphenylene, pyrenylene, benzothiophenylene,benzofuranylene,dibenzothiophenylene, arylthiazolylene, dibenzofuranylene, fluorenyleneand triphenylenylene.

Each of L1 and L2 may be one of non-substituted or substituted withalkyl, cyano and halogen phenylene, biphenylene and naphthalene.

The organic compound represented by the chemical formula 1 may include aphenanthroline moiety substituted with at least one aromatic ring. Sincethe organic compound has a relatively high decomposition temperature ora relatively high glass transition temperature due to the phenanthrolinemoiety, the organic compound has an excellent thermal stability. As aresult, the organic compound may not be deteriorated or spoiled even bya Joule's heat generated from driving of an element. Accordingly, thelifetime of an LED including the organic compound is extended and adriving voltage of the LED including the organic compound is reduced.

Further, since the organic compound represented by the chemical formula1 includes a phenanthroline moiety having a nitrogen atom of a hybridorbital of sp²of sufficient electrons, the organic compound has anexcellent electron transporting property. As a result, the organiccompound may be used for an electron transporting layer to efficientlysupply an electron to an emitting material layer. Specifically, anitrogen atom of a phenanthroline moiety is combined with an alkalimetal or an alkali earth metal of a dopant of an N type chargegeneration layer to form a gap state. As a result, an energy leveldifference between an N type charge generation layer and a P type chargegeneration layer is alleviated. Since the injection of an electron intothe N type charge generation layer is improved, the electrontransporting property from the N type charge generation layer to anadjacent electron transporting layer may be maximized.

In addition, the compound having a nitrogen atom is combined with analkali metal or an alkali earth metal in an N type charge generationlayer to prevent the alkali metal or the alkali earth metal fromdiffused into a P type charge generation layer. As a result, thereduction of an LED lifetime is prevented.

In an exemplary embodiment, an organic compound represented by thechemical formula 1 may be one of the following compounds:

Since the organic compounds above include a phenanthroline substitutedwith an aromatic ring, a thermal stability, an electron transportingproperty and an electron moving property are improved as compared with acompound which is not substituted with an aromatic ring. Since one ofthe organic compounds above is applied to an N type charge generationlayer of an LED having a tandem structure, the LED has an extendedlifetime, a reduced driving voltage and an improved emission efficiency.

[Light Emitting Diode and Display Device]

Since the organic compound represented by the chemical formula lincludesa phenanthroline moiety substituted with an aromatic ring, the organiccompound has an excellent electron transporting property and anexcellent thermal stability. As a result, an LED may have a reduceddriving voltage, an improved emission efficiency and an extendedlifetime by applying the organic compound represented by the chemicalformula 1 to an electron transporting layer and/or a charge generationlayer of the LED having a tandem structure.

FIG. 1 is a cross-sectional view showing a light emitting diode of atandem structure having two emitting parts according to a firstembodiment of the present disclosure.

In FIG. 1, a light emitting diode (LED) 100 according to a firstembodiment of the present disclosure includes first and secondelectrodes 110 and 120 spaced apart from each other and an organicemitting layer 130 between the first and second electrodes 110 and 120.The organic emitting layer 130 includes a first emitting part (ST1) 140between the first and second electrodes 110 and 120, a second emittingpart (ST2) 150 between the first emitting part 140 and the secondelectrode 120 and a charge generation layer (CGL) 160 between the firstand second emitting parts 140 and 150. The first emitting part 140includes a first emitting material layer (lower emitting material layer)144, and the second emitting part 150 includes a second emittingmaterial layer (upper emitting material layer) 154.

The first electrode 110 may be an anode where a hole is injected and mayinclude a material having a relatively high work function. For example,the first electrode 110 may include a transparent conductive materialsuch as indium tin oxide (ITO), indium zinc oxide (IZO) and zinc oxide(ZO). The second electrode 120 may be a cathode where an electron isinjected and may include a material having a relatively low workfunction. For example, the second electrode 120 may include a metallicmaterial such as aluminum (Al), magnesium (Mg) and aluminum magnesium(AlMg) alloy.

The first emitting part 140 may include a hole injecting layer 141between the first electrode 110 and the first emitting material layer144, a first hole transporting layer 142 between the hole injectinglayer 141 and the first emitting material layer 144 and a first electrontransporting layer (lower electron transporting layer) 146 between thefirst emitting material layer 144 and the charge generation layer 160.

The hole injecting layer 141 may improve an interface property betweenthe first electrode 120 of an inorganic material and the first holetransporting layer 142 of an organic material. For example, the holeinjecting layer 141 may include one of4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine(MTDATA), copperphthalocyanine(CuPc), tris(4-carbazoyl-9-ylphenyl)amine(TCTA),N,N′-di(naphthalen-1-yl)-N,N′-diphenylbenzidine(NPB),N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4″-diamine(NPD),1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile(HATCN),poly(3,4-ethylenedioxythiphene)polystyrene sulfonate(PEDOT/PSS)2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) and/orN-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine.

For example, the hole injecting layer 141 may have a thickness of about1 nm to about 150 nm. A hole injecting property is improved when thethickness of the hole injecting layer 141 is equal to or greater thanabout 1 nm, and an increase of a driving voltage due to an increase ofthe thickness is prevented when the thickness of the hole injectinglayer 141 is equal to or smaller than about 150 nm. The hole injectinglayer 141 may be omitted in another embodiment.

The first hole transporting layer 142 is disposed between the holeinjecting layer 141 and the first emitting material layer 144. The firstemitting material layer 144 is disposed between the first holetransporting layer 142 and the first electron transporting layer 146.The first electron transporting layer 146 is disposed between the firstemitting material layer 144 and the charge generation layer 160.

The second emitting part 150 may include a second hole transportinglayer (upper hole transporting layer) 152, a second emitting materiallayer (upper emitting material layer) 154, a second electrontransporting layer (upper electron transporting layer) 156 and anelectron injecting layer 158. The second hole transporting layer 152 isdisposed between the charge generation layer 160 and the second emittingmaterial layer 154. The second emitting material layer 154 is disposedbetween the second hole transporting layer 152 and the second electrode120. Further, the second electron transporting layer 156 is disposedbetween the second emitting material layer 154 and the second electrode120, and the electron injecting layer 158 is disposed between the secondelectron transporting layer 156 and the second electrode 120.

Each of the first and second hole transporting layers 142 and 152 mayinclude one ofN,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine(TPD),NPD, MTDATA, 1,3-bis(N-carbazolyl)benzene (mCP), CuPC, TCTA,tris(trifluorovinyl ether)-tris(4-carbazoyl-9-yl-phenyl)amine(TFV-TCTA), tris[4-(diethylamino)phenyl]amine),N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluorene-2-amine,tri-p-tolylamine,N-[1,1′-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-amine,4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) and/or1,1-bis(4-(N,N′-di(ptolyl)amino)phenyl)cyclohexane (TAPC).

For example, each of the first and second hole transporting layers 142and 152 may have a thickness of about 1 nm to about 150 nm. A holetransporting property is improved when the thickness of each of thefirst and second hole transporting layers 142 and 152 is equal to orgreater than about 1 nm, and an increase of a driving voltage due to anincrease of the thickness is prevented when the thickness of the firstand second hole transporting layers 142 and 152 is equal to or smallerthan about 150 nm. The first and second hole transporting layers 142 and152 may include the same material or may include different materials.

In an exemplary embodiment, the first and second emitting materiallayers 144 and 154 may include a host doped with a dopant and may emitdifferent colors. The dopant may be added to the host with a ratio ofabout 1 wt % to about 30 wt %.

For example, the first emitting material layer 144 may emit a blue (B),red (R), green (G) or yellow (Y) light. When the first emitting materiallayer 144 is a blue emitting layer, the first emitting material layer144 may include one of a blue emitting material layer, a dark blueemitting material layer and a sky blue emitting material layer.Alternatively, the first emitting material layer 144 may include one ofa blue emitting material layer and a red emitting material layer, a blueemitting material layer and a yellow-green emitting material layer, anda red emitting material layer and a green emitting material layer.

The second emitting material layer may include one of a red emittingmaterial layer, a green emitting material layer, a blue emittingmaterial layer and a yellow-green emitting material layer. In anexemplary embodiment, the first emitting material layer 144 may emit ablue light, and the second emitting material layer 154 may emit a greenlight, a yellow-green light or an orange light having a wavelengthlonger than a blue light.

For example, when the first emitting material layer 144 emits a bluelight, the first emitting material layer 144 may include at least onefluorescent host material selected from a group including anthracene andderivatives thereof, pyrene and derivatives thereof, and perylene andderivatives thereof doped with a fluorescent dopant.

A blue fluorescent host material for the first emitting material layer144 may include one of 4,4′-bis(2,2′-diphenylyinyl)-1,1′-biphenyl(DPVBi), 9,10-di-(2-naphtyl)anthracene (ADN),2,5,8,11-tetra-t-butylperylene (TBADN),2-tert-butyl-9,10-di(2-naphthyl)anthracene,2-methyl-9,10-di(2-naphtyl)anthracene (MADN) and/or2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole (TBPi).

A blue fluorescent dopant material for the first emitting material layer144 may include one of 4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl(BCzVBi) and/ordiphenyl-[4-(2-[1,1,4,1]terphenyl-4-yl-vinyl)-phenyl]-amine (BD-1) andmay include one selected from a group including spiro-DPVBi, spiro-CBP,distyrylbenzene (DSB) and derivaties thereof, distyryl arylene (DSA) andderivatives thereof, polyfluoorene (PF) polymer and polyphenylenevinylene (PPV) polymer. Alternatively, a blue dopant may include aniridium dopant as a phosphorescent dopant. Here, the first emittingmaterial layer 144 may include a sky blue emitting material layer or adeep blue emitting material layer as well as a blue emitting materiallayer. The light emitted from the first emitting material layer 144 mayhave a wavelength of about 440 nm to about 480 nm.

When the first emitting material layer 144 emits a green light, thefirst emitting material layer 144 may be a phosphorescent emittingmaterial layer including a host such as CBP and a dopant of an iridiumgroup (e.g., dp₂Ir(acac), op₂Ir(acac)). However, the first emittingmaterial layer 144 is not limited to that set forth herein.Alternatively, the first emitting material layer 144 may be afluorescent emitting material layer includingtris(8-hydroxyquinolinato)aluminum (Alq). Here, the light emitted fromthe first emitting material layer 144 may have a wavelength of about 510nm to about 570 nm.

When the first emitting material layer 144 emits a red light, the firstemitting material layer 144 may be a phosphorescent emitting materiallayer including a host such as CBP and a dopant of one selected from agroup including bis(1-phenylisoquinoline)acetylacetonate iridium(PIQIr(acac)), bis(1-phenylquinoline)acetylacetonate iridium(PQIr(acac)) and octaethylporphyrin platinum (PtOEP). However, the firstemitting material layer 144 is not limited to that set forth herein.

Alternatively, the first emitting material layer 144 may be afluorescent emitting material layer including1,3,4-oxadiazole:tris(dibenzoylmethane)mono(1,10-phentathroline)europium(III)(PBD:Eu(DBM)3(Phen)), perylene and derivatives thereof. The lightemitted from the first emitting material layer 144 may have a wavelengthof about 600 nm to about 650 nm.

When the first emitting material layer 144 emits a yellow light, thefirst emitting material layer 144 may have a single layered structure ofa yellow-green emitting material layer or a double layered structure ofa yellow-green emitting material layer and a green emitting materiallayer. For example, a yellow emitting material layer for the firstemitting material layer 144 may have at least one host selected from CBPand bis(2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminium (BAlq)and a yellow-green phosphorescent dopant. Here, the light emitted fromthe first emitting material layer 144 may have a wavelength of about 510nm to about 590 nm.

In an exemplary embodiment, to increase a red efficiency of the LED 100having a tandem structure, the first emitting material layer 144 mayinclude two emitting material layers, for example, a pair of ayellow-green emitting material layer and a red emitting material layeror a pair of a blue emitting material layer and a red emitting materiallayer.

When the second emitting material layer 154 is a yellow-green emittingmaterial layer, the second emitting material layer 154 may have a singlelayered structure of a yellow-green emitting material layer or a doublelayered structure of a yellow-green emitting material layer and a greenemitting material layer. When the second emitting material layer 154 hasa single layered structure of a yellow-green emitting material layer,the second emitting material layer 154 may include at least one hostselected from CBP and BAlq and a yellow-green phosphorescent dopant.However, the second emitting material layer 154 is not limited to thatset forth herein.

When the second emitting material layer 154 is a yellow emittingmaterial layer, the second emitting material layer 154 may include atleast one host selected from CBP and BAlq and a yellow phosphorescentdopant.

Each of the first and second electron transporting layers 146 and 156may improve an electron transporting in the first and second emittingparts 140 and 150. Each of the first and second electron transportinglayers 146 and 156 may include oxadiazole, triazole, phenanthroline,benzoxazole, benzothiazole, benzoimidazole, triazine and derivativesthereof.

For example, each of the first and second electron transporting layers146 and 156 may include an electron transporting material such asAlq3,2-biphenyl-4-yl-5-(4-t-butylphenyl)-1,3,4-oxadiazole (PBD),spiro-PBD, lithium quinolate (LiQ),2-[4-(9,10-Di-2-naphthalenyl-2-anthracenyl)phenyl]-1-phenyl-1H-benzimidazol,3-(biphenyl-4-yl)-5-(4-tertbutylphenyl)-4-phenyl-4H-1,2,4-triazole(TAZ), 4,7-diphenyl-1,10-phenanthroline (Bphen), tris(phenylquinoxaline(TPQ), 1,3,5-Tri[(3-pyridyl)-phen-3-yl]benzene (TmPyPB)and/or1,3,5-tris(N-phenylbenzimiazole-2-yl)benzene (TPBI). In addition,each of the first and second electron transporting layers 146 and 156may include an organic compound represented by the chemical formula 1.

Alternatively, each of the first and second electron transporting layers146 and 156 may be doped with an alkali metal or an alkali earth metal.The dopant for each of each of the first and second electrontransporting layers 146 and 156 may include an alkali metal such aslithium (Li), sodium (Na), potassium (K) and cesium (Cs) and/or analkali earth metal such as magnesium (Mg), strontium (Sr), barium (Ba)and radium (Ra). However, the dopant for each of the first and secondelectron transporting layers 146 and 156 is not limited to that setforth herein. The alkali metal or the alkali earth metal may be addedwith a ratio of about 1 wt % to about 20 wt %. However, the ratio is notlimited to that set forth herein.

Each of the first and second electron transporting layers 146 and 156may have a thickness of about 1 nm to about 150 nm. Decrease of anelectron transporting property is prevented when the thickness of eachof the first and second electron transporting layers 146 and 156 isequal to or greater than about 1 nm, and an increase of a drivingvoltage due to an increase of the thickness is prevented when thethickness of the first and second electron transporting layers 146 and156 is equal to or smaller than about 150 nm.

The electron injecting layer 158 may improve an electron injectingproperty. The electron injecting layer 158 may include an alkali halidematerial such as lithium fluoride (LiF), sodium fluoride (NaF),potassium fluoride (KF), rubidium fluoride (RbF), cesium fluoride (CsF),francium fluoride (FrF), beryllium fluoride (BeF₂), magnesium fluoride(MgF₂), calcium (CaF₂), barium fluoride (BaF₂) and radium fluoride(RaF₂) and/or an organic material such as lithium quinolate (LiQ),lithium benzoate, sodium stearate, Alq₃, BAlq, PBD, spiro-PBD and TAZ.

The electron injecting layer 158 may have a thickness of about 0.5 nm toabout 50 nm. A decrease of an electron injecting property is preventedwhen the thickness of the electron injecting layer 158 is equal to orgreater than about 0.5 nm, and an increase of a driving voltage due toan increase of the thickness is prevented when the thickness of theelectron injecting layer 158 is equal to or smaller than about 50 nm.

In an exemplary embodiment of the present disclosure, to improve acurrent efficiency in each of the first and second emitting parts 140and 150 and to improve distribution of charges, the charge generationlayer (CGL) 160 is disposed between the first and second emitting parts140 and 150, and the first and second emitting parts 140 and 150 areconnected to each other through the charge generation layer 160. Thecharge generation layer 160 may include a PN junction charge generationlayer where an N type charge generation layer 162 and a P type chargegeneration layer 164 are adjacently disposed and combined to each other.

The N type charge generation layer 162 is disposed between the firstelectron transporting layer 146 and the second hole transporting layer152, and the P type charge generation layer 164 is disposed between theN type charge generation layer 162 and the second hole transportinglayer 152. The charge generation layer 160 may supply an electron and ahole to the first and second emitting parts 140 and 150 by generating acharge such as an electron and a hole.

The N type charge generation layer 162 supplies an electron to the firstelectron transporting layer 146 of the first emitting part 140, and thefirst electron transporting layer 146 supplies an electron to the firstemitting material layer 144 adjacent to the first electrode 110. The Ptype charge generation layer 164 supplies a hole to the second holetransporting layer 152 of the second emitting part 150, and the secondhole transporting layer 152 supplies a hole to the second emittingmaterial layer 154 adjacent to the second electrode 120.

The P type charge generation layer 164 may include an organic materialdoped with a metal or a P type dopant. For example, the metal mayinclude an alloy of one or two selected from a group including aluminum(Al), copper (Cu), iron (Fe), lead (Pb), zinc (Zn), gold (Au), platinum(Pt), tungsten (W), indium (In), molybdenum (Mo), nickel (Ni) antitanium (Ti). The P type dopant may include F4-TCNQ, iodine (I), ironchloride (FeCl₃),iron fluoride (FeF₃) and antimony chloride (SbCl₅), andthe host may include at least one selected from a group including NPB,TPD, N,N,N′,N′-tetranaphthalenyl-benzidine (TNB) and HAT-CN.

When an electron moves from the N type charge generation layer 162 tothe first electron transporting layer 146, a driving voltage of the LED100 may increase due to difference in a lowest unoccupied molecularorbital (LUMO) energy level between the first electron transportinglayer 146 and the N type charge generation layer 162. To solve the aboveproblem, the organic compound represented by the chemical formula 1 maybe used for the N type charge generation layer 162 and/or the firstelectron transporting layer 146. Alternatively, the N type chargegeneration layer 162 may include a metallic compound such as an alkalimetal compound or an alkali earth metal compound as a dopant. The alkalimetal or the alkali earth metal may be added with a ratio of about 1 wt% to about 30 wt %. However, the ratio is not limited to that set forthherein.

An electron injecting property to the N type charge generation layer 162may be improved by doping the N type charge generation layer 162 withthe alkali metal or the alkali earth metal. For example, when the alkalimetal or the alkali earth metal is used as a dopant of the N type chargegeneration layer 162, the alkali metal or the alkali earth metal maycombine with the organic compound of the present disclosure to form agap state. Accordingly, the energy level difference between the N typecharge generation layer 162 and the P type charge generation layer 164is alleviated, and the electron injecting property from the N typecharge generation layer 162 to the first electron transporting layer 146may be improved.

The organic compound of the present disclosure includes a phenanthrolinemoiety substituted with at least one aromatic ring. Since the organiccompound has a relatively high decomposition temperature or a relativelyhigh glass transition temperature due to the phenanthroline moiety, theorganic compound has an excellent thermal stability. As a result, theorganic compound may not be deteriorated or spoiled even by a Joule'sheat generated from driving of an element. Accordingly, the lifetime ofthe LED 100 including the organic compound is extended and the drivingvoltage of the LED 100 including the organic compound is reduced.

Further, since the organic compound of the present disclosure includes aphenanthroline moiety having a nitrogen atom of a hybrid orbital of sp²of sufficient electrons, the organic compound has an excellent electrontransporting property. As a result, the organic compound may be used forthe electron transporting layers 146 and 156 and/or the chargegeneration layer 160.

Specifically, a nitrogen atom of a phenanthroline moiety is combinedwith the alkali metal or the alkali earth metal of the dopant of the Ntype charge generation layer to form a gap state. As a result, theenergy level difference between the N type charge generation layer andthe P type charge generation layer is alleviated. Since the injection ofan electron into the N type charge generation layer is improved, theelectron transporting property to the electron transporting layeradjacent to the N type charge generation layer may be maximized.

An electron may be efficiently transmitted from the N type chargegeneration layer 162 to the first electron transporting layer 146 byapplying the organic compound represented by the chemical formula 1 tothe N type charge generation layer 162.

Further, since the compound including a nitrogen atom is combined withthe alkali metal compound or the alkali earth metal compound of the Ntype charge generation layer, diffusion of the alkali metal compound orthe alkali earth metal compound to the P type charge generation layer isprevented. Accordingly, reduction of the LED lifetime is prevented.

FIG. 2 is a cross-sectional view showing a light emitting diode of atandem structure having three emitting parts according to a secondembodiment of the present disclosure.

In FIG. 2, a light emitting diode (LED) 200 according to a secondembodiment of the present disclosure includes first and secondelectrodes 210 and 220 facing and spaced apart from each other and anorganic emitting layer 230 between the first and second electrodes 210and 220. The organic emitting layer 230 includes a first emitting part(ST1) 240, a second emitting part (ST2) 250, a third emitting part (ST3)270, a first charge generation layer (CGL1) 260 and a second chargegeneration layer (CGL2) 280. At least four emitting parts and at leastthree charge generation layers may be disposed between the first andsecond electrodes 210 and 220 in another embodiment.

The first electrode 210 may be an anode where a hole is injected and mayinclude a material having a relatively high work function. For example,the first electrode 210 may include a transparent conductive materialsuch as indium tin oxide (ITO), indium zinc oxide (IZO) and zinc oxide(ZO). The second electrode 220 may be a cathode where an electron isinjected and may include a material having a relatively low workfunction. For example, the second electrode 220 may include a metallicmaterial such as aluminum (Al), magnesium (Mg) and aluminum magnesium(AlMg) alloy.

The first charge generation layer 260 is disposed between the first andsecond emitting parts 240 and 250, and the second charge generationlayer 280 is disposed between the second and third emitting parts 250and 270. The first emitting part 240, the first charge generation layer260, the second emitting part 250, the second charge generation layer280 and the third emitting part 270 are sequentially formed on the firstelectrode 210. The first emitting part 240 is disposed between the firstelectrode 210 and the first charge generation layer 260, the secondemitting part 250 is disposed between the first charge generation layer260 and the second charge generation layer 280, and the third emittingpart 270 is disposed between the second electrode 220 and the secondcharge generation layer 280.

The first emitting part 240 may include a hole injecting layer 241, afirst hole transporting layer 242, a first emitting material layer 244and a first electron transporting layer 246 on the first electrode 210.The hole injecting layer 241 and the first hole transporting layer 242are disposed between the first electrode 210 and the first emittingmaterial layer 244. The hole injecting layer 241 is disposed between thefirst electrode 210 and the first hole transporting layer 242. The firstelectron transporting layer 246 is disposed between the first emittingmaterial layer 244 and the first charge generation layer 260.

The hole injecting layer 241, the first hole transporting layer 242, thefirst emitting material layer 244 and the first electron transportinglayer 246 may have the same property as the hole transporting layer 141,the first hole transporting layer 142, the first emitting material layer144 and the first electron transporting layer 146, respectively, of FIG.1 and the illustrations thereof is omitted. For example, the firstemitting material layer 244 may be a blue (B) emitting material layer,and the light emitted from the first emitting material layer 244 mayhave a wavelength of about 440 nm to about 480 nm.

The second emitting part 250 may include a second hole transportinglayer 252, a second emitting material layer 254 and a second electrontransporting layer 256. The second hole transporting layer 252 isdisposed between the first charge generation layer 260 and the secondemitting material layer 254, and the second electron transporting layer256 is disposed between the second emitting material layer 254 and thesecond charge generation layer 280.

The second hole transporting layer 252, the second emitting materiallayer 254 and the second electron transporting layer 256 may have thesame property as the second hole transporting layer 152, the secondemitting material layer 154 and the second electron transporting layer156, respectively, of FIG. 1 and illustrations thereof is omitted. Forexample, the second emitting material layer 254 may be a yellow-green(YG) emitting material layer or a yellow emitting material layer, andthe light emitted from the second emitting material layer 254 may have awavelength of about 510 nm to about 590 nm or of about 460 nm to about510 nm.

The third emitting part 270 may include a third hole transporting layer272, a third emitting material layer 274, a third electron transportinglayer 276 and an electron injecting layer 278. The third holetransporting layer 272 is disposed between the second charge generationlayer 280 and the third emitting material layer 274, the third electrontransporting layer 276 is disposed between the third emitting materiallayer 274 and the second electrode 220, and the electron injecting layer278 is disposed between the third electron transporting layer 276 andthe second electrode 220.

The third hole transporting layer 272, the third electron transportinglayer 276 and the electron injecting layer 278 may have the sameproperty as the second hole transporting layer 152, the second electrontransporting layer 156 and the electron injecting layer 158,respectively, of FIG. 1 and illustrations thereof is omitted. The thirdemitting material layer 274 may have the same property as the firstemitting material layer 144 or the second emitting material layer 154.For example, the third emitting material layer 274 may be a blue (B)emitting material layer, and the light emitted from the third emittingpart 270 may have a wavelength of about 440 nm to about 480 nm. Inanother embodiment, the third emitting material layer 274 may be ayellow-green (YG) emitting material layer or a yellow emitting materiallayer, and the light emitted from the third emitting part 270 may have awavelength of about 460 nm to about 590 nm.

For example, at least one of the first electron transporting layer 246,the second electron transporting layer 256 and the third electrontransporting layer 276 may include an organic compound represented bythe chemical formula 1.

The first charge generation layer 260 is disposed between the firstemitting part 240 and the second emitting part 250, and the secondcharge generation layer 280 is disposed between the second emitting part250 and the third emitting part 270. Each of the first and second chargegeneration layers 260 and 280 may include a PN junction chargegeneration layer where an N type charge generation layer 262 and 282 anda P type charge generation layer 264 and 284 are combined to each other.

In the first charge generation layer 260, the N type charge generationlayer 262 is disposed between the first electron transporting layer 246and the second hole transporting layer 252, and the P type chargegeneration layer 264 is disposed between the N type charge generationlayer 262 and the second hole transporting layer 252.

In the second charge generation layer 280, the N type charge generationlayer 282 is disposed between the second electron transporting layer 256and the third hole transporting layer 272, and the P type chargegeneration layer 284 is disposed between the N type charge generationlayer 282 and the third hole transporting layer 272.

The first and second charge generation layers 260 and 280 may supply anelectron and a hole to the first, second and third emitting parts 240,250 and 270 by generating a charge such as an electron and a hole.

In the first charge generation layer 260, the N type charge generationlayer 262 may supply an electron to the first electron transportinglayer 246 of the first emitting part 240, and the P type chargegeneration layer 264 may supply a hole to the second hole transportinglayer 252 of the second emitting part 250.

In the second charge generation layer 280, the N type charge generationlayer 282 may supply an electron to the second electron transportinglayer 256 of the second emitting part 250, and the P type chargegeneration layer 284 may supply a hole to the third hole transportinglayer 272 of the third emitting part 270.

The P type charge generation layers 264 and 284 may include an organicmaterial doped with a metal or a P type dopant. For example, the metalmay include an alloy of one or two selected from a group includingaluminum (Al), copper (Cu), iron (Fe), lead (Pb), zinc (Zn), gold (Au),platinum (Pt), tungsten (W), indium (In), molybdenum (Mo), nickel (Ni)an titanium (Ti). The P type dopant may include F4-TCNQ, iodine (I),iron chloride (FeCl₃),iron fluoride (FeF₃) and antimony chloride(SbCl₅), and the host may include at least one selected from a groupincluding NPB, TPD, TNB and HAT-CN.

When an electron moves from the N type charge generation layers 262 and282 to the first and second electron transporting layers 246 and 256, adriving voltage of the LED 200 may increase due to difference in a LUMOenergy level between the first and second electron transporting layers246 and 256 and the N type charge generation layers 262 and 282.

To solve the above problem, the organic compound of the presentdisclosure may be used for at least one of the N type charge generationlayers 262 and 282 and/or at least one of the first and second electrontransporting layers 246 and 256. Alternatively, the N type chargegeneration layers 262 and 282 may include a metallic compound such as analkali metal or an alkali earth metal as a dopant.

For example, the N type charge generation layers 262 and 282 may furtherinclude at least one selected from a group including lithium quinolate(LiQ), lithium fluoride (LiF), sodium fluoride (NaF), potassium fluoride(KF), rubidium fluoride (RbF), cesium fluoride (CsF), francium fluoride(FrF), beryllium fluoride (BeF₂), magnesium fluoride (MgF₂), calciumfluoride (CaF₂), strontium fluoride (SrF₂), barium fluoride (BaF₂) andradium fluoride (RaF₂). However, the material for the N type chargegeneration layers 262 and 282 is not limited to that set forth herein.

An electron injecting property to the N type charge generation layers262 and 282 may be improved by doping the N type charge generationlayers 262 and 282 with the alkali metal or the alkali earth metal.

The organic compound of the present disclosure includes a phenanthrolinemoiety substituted with at least one aromatic ring. Since the organiccompound has a relatively high decomposition temperature or a relativelyhigh glass transition temperature due to the phenanthroline moiety, theorganic compound has an excellent thermal stability. As a result, theorganic compound may not be deteriorated or spoiled even by a Joule'sheat generated from driving of an element. Accordingly, a lifetime ofthe LED 200 including the organic compound is extended and a drivingvoltage of the LED 200 including the organic compound is reduced.

Further, since the organic compound of the present disclosure includes aphenanthroline moiety having a nitrogen atom of a hybrid orbital of sp²of sufficient electrons, the organic compound has an excellent electrontransporting property. As a result, the organic compound may be used forthe electron transporting layers 246, 256 and 276 and/or the chargegeneration layers 260 and 280.

Specifically, a nitrogen atom of a phenanthroline moiety is combinedwith the alkali metal or the alkali earth metal of the dopant of the Ntype charge generation layer to form a gap state. As a result, theenergy level difference between the N type charge generation layer andthe P type charge generation layer is alleviated. Since the injection ofan electron into the N type charge generation layer is improved, theelectron transporting property to the electron transporting layeradjacent to the N type charge generation layer may be maximized.

Further, since the compound including a nitrogen atom is combined withthe alkali metal compound or the alkali earth metal compound of the Ntype charge generation layer, diffusion of the alkali metal compound orthe alkali earth metal compound to the P type charge generation layer isprevented. Accordingly, reduction of the LED lifetime is prevented.

The LED of the present disclosure may be applied to an OLED displaydevice and a lighting apparatus. FIG. 3 is a cross-sectional viewshowing an organic light emitting diode display device according to athird embodiment of the present disclosure.

In FIG. 3, an organic light emitting diode (OLED) display device 300includes a substrate 301, a light emitting diode (LED) 400 and anencapsulation film 390 covering the LED 400. A driving thin filmtransistor (TFT) Td and the LED 400 connected to the driving TFT Td areformed on the substrate 301.

Although not shown, a gate line, a data line, a power line, a switchingTFT and a storage capacitor are formed on the substrate 301. The gateline and the data line cross each other to define a pixel region, andthe power line is disposed to be parallel to one of the gate line andthe data line. The switching TFT is connected to the gate line and thedata line, and the storage capacitor is connected to the power line andthe switching TFT.

The driving TFT Td is connected to the switching TFT and includes asemiconductor layer 310, a gate electrode 330, a source electrode 352and a drain electrode 354.

The semiconductor layer 310 is formed on the substrate 301 and mayinclude an oxide semiconductor material or polycrystalline silicon. Whenthe semiconductor layer 310 includes an oxide semiconductor material, alight shielding pattern (not shown) may be formed under thesemiconductor layer 310. Since a light incident to the semiconductorlayer 310 is blocked by the light shielding pattern, deterioration ofthe semiconductor layer 310 due to a light may be prevented. When thesemiconductor layer 310 includes polycrystalline silicon, both sideportions of the semiconductor layer 310 may be doped with impurities.

A gate insulating layer 320 of an insulating material is formed on anentire surface of the substrate 301 having the semiconductor layer 310.The gate insulating layer 320 may include an inorganic insulatingmaterial such as silicon oxide and silicon nitride.

A gate electrode 330 of a conductive material such as a metal is formedon the gate insulating layer 320 corresponding to a central portion ofthe semiconductor layer 310. The gate electrode 330 is connected to theswitching TFT.

An interlayer insulating layer 340 of an insulating material is formedon an entire surface of the substrate 301 having the gate electrode 330.The interlayer insulating layer 340 may include an inorganic insulatingmaterial such as silicon oxide and silicon nitride or an organicinsulating material such as benzocyclobutene and photoacryl.

The interlayer insulating layer 340 has first and second semiconductorcontact holes 342 and 344 exposing both side portions of thesemiconductor layer 310. The first and second semiconductor contactholes 342 and 344 are disposed at sides of the gate electrode 330 andspaced apart from the gate electrode 330.

A source electrode 352 and a drain electrode 354 of a conductivematerial such as a metal are formed on the interlayer insulating layer340. The source electrode 352 and the drain electrode 354 are spacedapart from each other with respect to the gate electrode 330 as a centerand are connected to the both side portions of the semiconductor layer310 through the first and second semiconductor contact holes 342 and344, respectively. The source electrode 352 is connected to the powerline (not shown).

The semiconductor layer 310, the gate electrode 330, the sourceelectrode 352 and the drain electrode 354 constitute the driving TFT Tdhaving a coplanar structure where the gate electrode 330, the sourceelectrode 352 and the drain electrode 354 are disposed over thesemiconductor layer 310.

In another embodiment, the driving TFT Td may have an inverted staggeredstructure where the gate electrode is formed under the semiconductorlayer and the source and drain electrodes are formed over thesemiconductor layer. When the driving TFT Td has an inverted staggeredstructure, the semiconductor layer may include amorphous silicon. Theswitching TFT may have substantially the same structure as the drivingTFT Td.

The OLED display device 300 may include a color filter layer 360filtering a light emitted from the LED 400. For example, the colorfilter layer 360 may selectively absorb one of red (R), green (G), blue(B) and white (W) colored lights. Red, green and blue color filters maybe formed in pixel regions, respectively, and may be disposed to overlapan organic emitting layer 430 of the LED 400. The OLED display device300 may display a full color image by using the color filter layer 360.

For example, when the OLED display device 300 has a bottom emissiontype, the color filter layer 360 may be formed on the interlayerinsulating layer 340 corresponding to the LED 400. When the OLED displaydevice 300 has a top emission type, the color filter layer 360 may beformed over a second electrode 420 of the LED 400. The color filterlayer 360 may have a thickness of about 2 μm to about 5 μm. The LED 400may include a white LED having a tandem structure of FIGS. 1 and 2.

A passivation layer 370 is formed on the driving TFT Td and has a draincontact hole exposing the drain electrode 354 of the driving TFT Td.

A first electrode 410 is formed on the passivation layer 370 in eachpixel region and is connected to the drain electrode 354 of the drivingTFT Td through the drain contact hole 372.

The first electrode 410 may be an anode of a conductive material havinga relatively high work function. For example, the first electrode 410may include a transparent conductive material such as indium tin oxide(ITO), indium zinc oxide (IZO) and zinc oxide (ZO).

When the OLED display device 300 has a top emission type, a reflectingelectrode or a reflecting layer may be further formed under the firstelectrode 410. For example, the reflecting electrode or the reflectinglayer may include one of aluminum (Al), silver (Ag), nickel (Ni) andaluminum palladium copper (APC) alloy.

A bank layer 380 is formed on the passivation layer 370 to cover an edgeportion of the first electrode 410. The bank layer 380 exposes a centralportion of the first electrode 410 corresponding to the pixel region.

An organic emitting layer 430 is formed on the first electrode 410. Forexample, the organic emitting layer 430 may include at least twoemitting parts as shown in FIGS. 1 and 2 such that the LED 400 has atandem structure.

A second electrode 420 is formed on an entire surface of the substrate301 having the organic emitting layer 430. The second electrode 420 maybe a cathode of a conductive material having a relatively low workfunction. For example, the second electrode 420 may include a metallicmaterial such as aluminum (Al), magnesium (Mg) and aluminum magnesium(AlMg) alloy.

The first electrode 410, the organic emitting layer 430 and the secondelectrode 420 constitute the LED 400.

An encapsulation film 390 is formed on the second electrode 420 toprevent penetration of external moisture into the LED 400. Although notshown, the encapsulation film 390 may have a triple layered structureincluding a first inorganic layer, an organic layer and a secondinorganic layer. However, the encapsulation film 390 is not limited tothat set forth herein.

The organic compound of the present disclosure includes a phenanthrolinemoiety substituted with at least one aromatic ring. Since the organiccompound has a relatively high decomposition temperature or a relativelyhigh glass transition temperature due to the phenanthroline moiety, theorganic compound has an excellent thermal stability. Accordingly, alifetime of the LED 400 including the organic compound is extended and adriving voltage of the LED 400 including the organic compound isreduced.

Further, since the organic compound of the present disclosure includes aphenanthroline moiety having a nitrogen atom of a hybrid orbital of sp²of sufficient electrons, the organic compound has an excellent electrontransporting property. A nitrogen atom of a phenanthroline moiety iscombined with the alkali metal or the alkali earth metal of the dopantof the N type charge generation layer to form a gap state. As a result,the energy level difference between the N type charge generation layerand the P type charge generation layer is alleviated. Since theinjection of an electron into the N type charge generation layer isimproved, the electron transporting property to the electrontransporting layer adjacent to the N type charge generation layer may bemaximized.

Further, since the compound including a nitrogen atom is combined withthe alkali metal compound or the alkali earth metal compound of the Ntype charge generation layer, diffusion of the alkali metal compound orthe alkali earth metal compound to the P type charge generation layer isprevented. Accordingly, reduction of the LED lifetime is prevented.

SYNTHESIS EXAMPLE 1 Synthesis of Compound EN-016

After a mixture was formed by dissolving4,4,5,5-tetramethyl-2-(1-(phenanthren-10-yl)naphthalen-4-yl)-1,3,2-dioxaborolane(6.0 g, 13.94 mmol), 2-bromo-1,10-phenanthroline (4.20 g, 12.57 mmol),tetrakis-triphenylphosphine palladium(0) (Pd(PPh₃)₄) (0.50 g, 0.70mmol), 4M potassium carbonate aqueous solution (10 mL), toluene 30 mL,ethanol (EtOH) 10 mL under a nitrogen atmosphere, the mixture wasrefluxed and stirred for 12 hours. After a reaction was finished, H₂O 50mL was added to the mixture, the mixture was stirred for 3 hours and avacuum filtration was performed. After the mixture was divided through acolumn chromatography using methylene chloride (MC) and hexane as aneluent, the mixture was re-crystallized by using MC to obtain a compoundEN-016 (6.25 g, transference number of 80.3%).

COMPARATIVE SYNTHESIS EXAMPLE 1 Synthesis of Compound EN-016-1

After a mixture was formed by dissolving4,4,5,5-tetramethyl-2-(1-(phenanthren-10-yl)naphthalen-4-yl)-1,3,2-dioxaborolane(5.0 g, 19.38 mmol), 2-bromo-9-phenyl-1,10-phenanthroline (8.50 g, 19.76mmol), tetrakis-triphenylphosphine palladium(0) (Pd(PPh₃)₄) (1.14 g,0.99 mmol), 4M potassium carbonate aqueous solution (10 mL), toluene 30mL, ethanol (EtOH) 10 mL under a nitrogen atmosphere, the mixture wasrefluxed and stirred for 12 hours. After there action was finished, H₂O50 mL was added to the mixture, the mixture was stirred for 3 hours andvacuum filtration was performed. After the mixture was divided through acolumn chromatography using methylene chloride (MC) and hexane as aneluent, the mixture was re-crystallized by using MC to obtain a compoundEN-016-1 (7.94 g, transference number of 85.1%).

SYNTHESIS EXAMPLE 2 Synthesis of Compound EN-145

After a mixture was formed by dissolving2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-9-phenyl-1,10-phenanthroline(5.0 g, 10.91 mmol), 4-(4-bromophenyl)-2,6-diphenylpyrimidine (4.80 g,12.40 mmol), tetrakis-triphenylphosphine palladium(0) (Pd(PPh₃)₄) (0.63g, 0.55 mmol), 4M potassium carbonate aqueous solution (10 mL), toluene30 mL, ethanol (EtOH) 10 mL under a nitrogen atmosphere, the mixture wasrefluxed and stirred for 12 hours. After the reaction was finished, H₂O50 mL was added to the mixture, the mixture was stirred for 3 hours andvacuum filtration was performed. After the mixture was divided through acolumn chromatography using methylene chloride (MC) and hexane as aneluent, the mixture was re-crystallized by using MC to obtain a compoundEN-145 (5.01 g, transference number of 72.3%).

COMPARATIVE SYNTHESIS EXAMPLE 2 Synthesis of Compound EN-145-1

After a mixture was formed by dissolving2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-1,10-phenanthroline(5.0 g, 13.08 mmol), 4-(4-bromophenyl)-2,6-diphenylpyrimidine (6.10 g,15.96 mmol), tetrakis-triphenylphosphine palladium(0) (Pd(PPh₃)₄) (0.75g, 0.65 mmol), 4M potassium carbonate aqueous solution (10 mL), toluene30 mL, ethanol (EtOH) 10 mL under a nitrogen atmosphere, the mixture wasrefluxed and stirred for 12 hours. After there action was finished, H₂O50 mL was added to the mixture, the mixture was stirred for 3 hours andvacuum filtration was performed. After the mixture was divided through acolumn chromatography using methylene chloride (MC) and hexane as aneluent, the mixture was re-crystallized by using MC to obtain a compoundEN-145-1 (5.56 g, transference number of 75.6%).

SYNTHESIS EXAMPLE 3 Synthesis of Compound EN-160

After a mixture was formed by dissolving2-(1-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)naphthalen-4-yl)-1,10-phenanthroline(5.5 g, 10.82 mmol), 4-(4-bromophenyl)-2,6-diphenylpyrimidine (4.50 g,11.63 mmol), tetrakis-triphenylphosphine palladium(0) (Pd(PPh₃)₄) (0.63g, 0.54 mmol), 4M potassium carbonate aqueous solution (10 mL), toluene30 mL, ethanol (EtOH) 10 mL under a nitrogen atmosphere, the mixture wasrefluxed and stirred for 12 hours. After there action was finished, H₂O50 mL was added to the mixture, the mixture was stirred for 3 hours andvacuum filtration was performed. After the mixture was divided through acolumn chromatography using methylene chloride (MC) and hexane as aneluent, the mixture was re-crystallized by using MC to obtain a compoundEN-160 (5.03 g, transference number of 72.8%).

COMPARATIVE SYNTHESIS EXAMPLE 3 Synthesis of Compound EN-160-1

After a mixture was formed by dissolving2-(1-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)naphthalen-4-yl)-9-phenyl-1,10-phenanthroline(6.0 g, 13.88 mmol), 4-(4-bromophenyl)-2,6-diphenylpyrimidine (6.0 g,15.50 mmol), tetrakis-triphenylphosphine palladium(0) (Pd(PPh₃)₄) (0.80g, 0.69 mmol), 4M potassium carbonate aqueous solution (10 mL), toluene30 mL, ethanol (EtOH) 10 mL under a nitrogen atmosphere, the mixture wasrefluxed and stirred for 12 hours. After there action was finished, H₂O50 mL was added to the mixture, the mixture was stirred for 3 hours andvacuum filtration was performed. After the mixture was divided through acolumn chromatography using methylene chloride (MC) and hexane as aneluent, the mixture was re-crystallized by using MC to obtain a compoundEN-160-1 (6.11 g, transference number of 71.8%).

EXPERIMENTAL EXAMPLE 1 Estimation of Thermal Stability and ElectronMoving Property

A thermal stability and an electron moving property of the compounds ofthe synthesis examples 1 to 3 and the comparative synthesis examples 1to 3 were estimated. A thermal stability was obtained by measuring adecomposition temperature (1%, 5%) and a glass transition temperature(Tg) through a thermogravimetric analysis (TGA) and a differentialscanning calorimeter (DSC). An electron moving property was obtained bycalculating an electron affinity (EA), a reorganization energy(λ_(electron)) and a ratio of rate constants of an electron and a hole(k_(et)(e)/k_(et)(h)) using a density functional theory (B3LYP/6-31G*).Results of measurement and estimation are illustrated in a followingtable.

TABLE 1 Simulation Analysis Thermal Analysis (° C.) Electron Td (1%) Td(5%) Tg Affinity λ_(electron) k_(et) (e)/k_(et) (h) EN-016 415 456 1570.57 0.29 1.18 EN-016-1 401 442 151 0.44 0.38 1.11 EN-145 465 506 1380.96 0.27 0.30 En-145-1 436 477 131 0.89 0.29 0.27 EN-160 471 510 1470.92 0.31 0.43 EN-160-1 445 588 141 0.72 0.35 0.31

In TABLE 1, the compound according to the present disclosure including aphenanthroline moiety where a phenyl group corresponding to an arylgroup is substituted has a higher decomposition temperature and a higherglass transition temperature as compared with the compound where aphenyl group is not substituted. As a result, the thermal stability isimproved. Further, the compound including a phenanthroline moiety wherea phenyl group is substituted has a greater electron affinity (EA) ascompared with the compound where a phenyl group is not substituted. As aresult, the compound including a phenanthroline moiety where a phenylgroup is substituted may receive an electron more easily as comparedwith the compound where a phenyl group is not substituted. Specifically,a material for the N type charge generation layer (n-CGL) is required tohave an excellent property of receiving an electron from the P typecharge generation layer (p-CGL) and transmitting an electron to theelectron transporting layer (ETL). Since the compound including aphenanthroline moiety where a phenyl group is substituted has a reducedreorganization energy (λ_(electron)) and a increased ratio of rateconstants of an electron and a hole (k_(et)(e)/k_(et)(h)), the compoundincluding a phenanthroline moiety where a phenyl group is substitutedhas a superior negative ion stability and a superior electron movingproperty as compared with the compound where a phenyl group is notsubstituted.

Embodiment 1: Fabrication of Light Emitting Diode of Tandem Structure

A light emitting diode (LED) of a tandem structure including threeemitting parts by using the compound EN-016 of the synthesis example 1for the N type charge generation layer was fabricated. After an indiumtin oxide (ITO) substrate was patterned to have an emission area of 2mm*2 mm, the ITO substrate was cleaned using an ultraviolet (UV) andozone. In a vacuum deposition chamber having a pressure of 5*10⁻⁸ to7*10⁻⁸ torr, the following layers were sequentially formed on the ITOsubstrate.

Hole Injecting Layer (NPD doped with 10% of F4-TCNQ) 100 Å, First HoleTransporting Layer (NPD) 1200 Å, First Emitting Material Layer (BlueEmitting Material Layer, anthracene host doped with 4% of pyrene dopant)200 Å, First Electron Transporting Layer(1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene (TmPyPB) 100 Å,First N TypeCharge Generation Layer (EN-016 doped with 2% of Li) 100 Å,First P TypeCharge Generation Layer (NPD doped with 10% of F4-TCNQ) 200 Å, SecondHole Transporting Layer (NPD) 200 Å, Second Emitting Material Layer(Yellow Emitting Material Layer, CBP host doped with 10% of Ir complex)200 Å, Second Electron Transporting Layer (Alq3), Second N Type ChargeGeneration Layer(EN-016 doped with 2% of Li) 100 Å,Second P Type ChargeGeneration Layer (NPD doped with 10% of F4-TCNQ)200 Å,Third HoleTransporting Layer (NPD) 200 Å,Third Emitting Material Layer (YellowEmitting Material Layer, CBP host doped with 10% of Ir complex)200Å,Third Electron Transporting Layer (TmPyPB) 100 Å, Electron InjectingLayer (LiF) 10 Å, Cathode (aluminum) 200 Å.

COMPARATIVE EXAMPLE 1 Fabrication of Light Emitting Diode of TandemStructure

Through a process the same as that of the embodiment 1 except that thecompound EN-016-1 of the comparative synthesis example 1 was used forthe host of the first and second N type charge generation layers insteadof the compound EN-016, the LED was fabricated.

EXPERIMENTAL EXAMPLE 2 Estimation of Property of Light Emitting Diode

Driving properties of the LED of a tandem structure of the embodiment 1and the comparative example 1 were estimated. FIGS. 4A to 4D are graphsshowing a voltage-current density property, a brightness-currentefficiency property, a brightness-external quantum efficiency (EQE)property and a lifetime property, respectively, of light emitting diodesof the embodiment 1 and the comparative example 1. The driving voltageof the LED of the embodiment 1 is reduced by about 0.2V as compared withthe driving voltage of the LED of the comparative example 1. The currentefficiency of the LED of the embodiment 1 is increased by about 2% ascompared with the current efficiency of the LED of the comparativeexample 1. The external quantum efficiency of the LED of the embodiment1 is similar to the external quantum efficiency of the LED of thecomparative example 1. The lifetime of the LED of the embodiment 1 isextended by about 10% as compared with the lifetime of the LED of thecomparative example 1.

Embodiment 2: Fabrication of Light Emitting Diode of Tandem Structure

Through a process the same as that of the embodiment 1 except that thecompound EN-145 of the synthesis example 2 was used for the host of thefirst and second N type charge generation layers instead of the compoundEN-016, the LED was fabricated.

COMPARATIVE EXAMPLE 2 Fabrication of Light Emitting Diode of TandemStructure

Through a process the same as that of the embodiment 1 except that thecompound EN-145-1 of the comparative synthesis example 2 was used forthe host of the first and second N type charge generation layers insteadof the compound EN-016, the LED was fabricated.

EXPERIMENTAL EXAMPLE 3 Estimation of Property of Light Emitting Diode

Driving properties of the LED of a tandem structure of the embodiment 2and the comparative example 2 were estimated. FIGS. 5A to 5D are graphsshowing a voltage-current density property, a brightness-currentefficiency property, a brightness-external quantum efficiency (EQE)property and a lifetime property, respectively, of light emitting diodesof the embodiment 2 and the comparative example 2. The driving voltageof the LED of the embodiment 2 is similar to the driving voltage of theLED of the comparative example 2. The current efficiency of the LED ofthe embodiment 2 is increased by about 1% as compared with the currentefficiency of the LED of the comparative example 2. The external quantumefficiency of the LED of the embodiment 2 is increased by about 1% ascompared with the external quantum efficiency of the LED of thecomparative example 2. The lifetime of the LED of the embodiment 2 isextended by about 29% as compared with the lifetime of the LED of thecomparative example 2.

Embodiment 3: Fabrication of Light Emitting Diode of Tandem Structure

Through a process the same as that of the embodiment 1 except that thecompound EN-160 of the synthesis example 3 was used for the host of thefirst and second N type charge generation layers instead of the compoundEN-016, the LED was fabricated.

COMPARATIVE EXAMPLE 3 Fabrication of Light Emitting Diode of TandemStructure

Through a process the same as that of the embodiment 1 except that thecompound EN-160-1 of the comparative synthesis example 3 was used forthe host of the first and second N type charge generation layers insteadof the compound EN-016, the LED was fabricated.

EXPERIMENTAL EXAMPLE 4 Estimation of Property of Light Emitting Diode

Driving properties of the LED of a tandem structure of the embodiment 3and the comparative example 3 were estimated. FIGS. 6A to 6D are graphsshowing a voltage-current density property, a brightness-currentefficiency property, a brightness-external quantum efficiency (EQE)property and a lifetime property, respectively, of light emitting diodesof the embodiment 3 and the comparative example 3. The driving voltageof the LED of the embodiment 3 is reduced by about 0.2V as compared withthe driving voltage of the LED of the comparative example 3. The currentefficiency of the LED of the embodiment 3 is increased by about 5% ascompared with the current efficiency of the LED of the comparativeexample 3. The external quantum efficiency of the LED of the embodiment3 is increased by about 1% as compared with the external quantumefficiency of the LED of the comparative example 3. The lifetime of theLED of the embodiment 3 is extended by about 15% as compared with thelifetime of the LED of the comparative example 3.

As shown in the results of the experimental examples 2 to 4, the organiccompound including a phenanthroline moiety where a phenyl group issubstituted has the similar or reduced driving voltage as compared withthe organic compound where a phenyl group is not substituted. Theorganic compound including a phenanthroline moiety where a phenyl groupis substituted has the similar or improved current efficiency and thesimilar or improved external quantum efficiency as compared with theorganic compound where a phenyl group is not substituted. Specifically,since the thermal stability and the electron moving property areimproved due to a phenyl group, the lifetime of the LED is greatlyextended.

Consequently, the organic compound of the present disclosure includes aphenanthroline moiety substituted with at least one aromatic ring. Sincethe organic compound has a relatively high decomposition temperature ora relatively high glass transition temperature due to the phenanthrolinemoiety, the organic compound has an excellent thermal stability. As aresult, the organic compound may not be deteriorated or spoiled even bya Joule's heat generated from driving of an element. Accordingly, alifetime of the LED including the organic compound is extended and adriving voltage of the LED including the organic compound is reduced.

Further, since the organic compound of the present disclosure includes aphenanthroline moiety having a nitrogen atom of a hybrid orbital of sp²of sufficient electrons, the organic compound has an excellent electrontransporting property. Accordingly, the organic compound of the presentdisclosure may be used for the electron transporting layer. A nitrogenatom of a phenanthroline moiety is combined with the alkali metal or thealkali earth metal of the dopant of the N type charge generation layerto form a gap state. As a result, the energy level difference betweenthe N type charge generation layer and the P type charge generationlayer is alleviated. Since the injection of an electron into the N typecharge generation layer is improved, the electron transporting propertyto the electron transporting layer adjacent to the N type chargegeneration layer may be maximized.

An electron may be efficiently transmitted from the N type chargegeneration layer to the electron transporting layer by applying theorganic compound of the present disclosure to the N type chargegeneration layer.

Further, since the compound including a nitrogen atom is combined withthe alkali metal compound or the alkali earth metal compound of the Ntype charge generation layer, diffusion of the alkali metal compound orthe alkali earth metal compound to the P type charge generation layer isprevented. Accordingly, reduction of the LED lifetime is prevented.

A number of examples have been described above. Nevertheless, it will beunderstood that various modifications may be made. For example, suitableresults may be achieved if the described techniques are performed in adifferent order and/or if components in a described system,architecture, device, or circuit are combined in a different mannerand/or replaced or supplemented by other components or theirequivalents. Accordingly, other implementations are within the scope ofthe following claims.

What is claimed is:
 1. An organic compound selected from:


2. A light emitting diode, comprising: first and second electrodesfacing each other; a first emitting part between the first and secondelectrodes and including a first emitting material layer and an electrontransporting layer; a second emitting part between the first emittingpart and the second electrode and including a second emitting materiallayer; and a first charge generation layer between the first and secondemitting parts, wherein at least one of the electron transporting layerand the first charge generation layer includes an organic compoundrepresented by the following chemical formula 1, wherein the firstcharge generation layer includes an N type charge generation layer and aP type charge generation layer, and the N type charge generation layerincludes the organic compound:

wherein, each of R₁ to R₆ is independently one of hydrogen, deuterium,tritium, a non-substituted alkyl group of C1 to C20, a substituted alkylgroup of C1 to C20, a non-substituted alkoxy group of C1 to C20, asubstituted alkoxy group of C1 to C20, a non-substituted aryl group ofC5 to C60, a substituted aryl group of C5 to C60 and a non-substitutedhetero aryl group of C4 to C60, and a substituted hetero aryl group ofC4 to C60; each of L₁ and L₂ is independently one of a non-substitutedarylene group of C5 to C60, a substituted arylene group of C5 to C60, anon-substituted hetero arylene group of C5 to C60, and a substitutedhetero arylene group of C5 to C60; a is 1; and each of Ar₁ and Ar₂ isindependently one of a non-substituted aryl group of C5 to C60, asubstituted aryl group of C5 to C60, a non-substituted hetero aryl groupof C4 to C30, and a substituted hetero aryl group of C4 to C30; with theproviso that when R₁ to R₆ are each hydrogen, L₁ is phenylene, L₂ isanthracenylene and Ar₁ is phenyl, then Ar₂ cannot be a naphthyl group.3. The light emitting diode of claim 2, wherein the N type chargegeneration layer includes one of an alkali metal and an alkali earthmetal.
 4. The light emitting diode of claim 2, further comprising: athird emitting part between the second emitting part and the secondelectrode; and a second charge generation layer between the secondemitting part and the third emitting part, wherein the second chargegeneration layer includes the organic compound.
 5. An organic lightemitting diode display device, comprising: a substrate; a light emittingdiode on the substrate; and a driving element between the substrate andthe light emitting diode, wherein the light emitting diode comprises:first and second electrodes facing each other; a first emitting partbetween the first and second electrodes and including a first emittingmaterial layer and an electron transporting layer; a second emittingpart between the first emitting part and the second electrode andincluding a second emitting material layer; and a first chargegeneration layer between the first and second emitting parts, wherein atleast one of the electron transporting layer and the first chargegeneration layer includes an organic compound selected from:

and wherein the driving element is connected to the first electrode. 6.The organic light emitting diode display device of claim 5, furthercomprising a color filter layer between the substrate and the firstelectrode.
 7. The organic light emitting diode display device of claim5, further comprising a color filter layer on the light emitting diode.8. The light emitting diode of claim 2, wherein the organic compound isselected from:


9. An organic light emitting diode display device comprising: asubstrate; a light emitting diode on the substrate; and a drivingelement between the substrate and the light emitting diode, wherein thelight emitting diode comprises: first and second electrodes facing eachother; a first emitting part between the first and second electrodes andincluding a first emitting material layer and an electron transportinglayer; a second emitting part between the first emitting part and thesecond electrode and including a second emitting material layer; and afirst charge generation layer between the first and second emittingparts, wherein at least one of the electron transporting layer and thefirst charge generation layer includes an organic compound by afollowing chemical formula 1, wherein the first charge generation layerincludes an N type charge generation layer and a P type chargegeneration layer, and the N type charge generation layer includes theorganic compound:

wherein, each of R₁ to R₆ is independently one of hydrogen, deuterium,tritium, a non-substituted or substituted alkyl group of C1 to C20, anon-substituted or substituted alkoxy group of C1 to C20, anon-substituted or substituted aryl group of C5 to C60 and anon-substituted or substituted hetero aryl group of C4 to C60; each ofL₁ and L₂ is independently one of a non-substituted or substitutedarylene group of C5 to C60 and a non-substituted or substituted heteroarylene group of C5 to C60, a is 1, and each of Ar₁ and Ar₂ isindependently one of a non-substituted aryl group of C5 to C60, asubstituted aryl group of C5 to C60, a non-substituted hetero aryl groupof C4 to C30, and a substituted hetero aryl group of C4 to C30, with theproviso that when R₁ to R₆ are each hydrogen, L₁ is phenylene, L₂ isanthracenylene, and Ar₁ is phenyl, then Ar₂ cannot be a naphthyl group,and wherein the driving element is connected to the first electrode. 10.The organic light emitting diode display device of claim 9, wherein theAr₂ is the non-substituted hetero aryl group of C4 to C30 or thesubstituted hetero aryl group of C4 to C30.